The invention relates to electronic sensors and more particularly to electronic sensor assemblies having a cap retained onto the sensor with a bracket.
Electronic sensors which are suitable for detecting discontinuities, such as gear teeth, along a target surface are well known and used in automotive applications such as brake systems, cruise control systems, transmission systems, as well as others. In its environment of use, the sensor apparatus requires a support structure, a sensor housing, and a means for mounting the sensor housing onto the support structure. The stack-up of tolerances of the components comprising the sensor within the housing in addition to the stack-up of tolerances associated with connection to the mounting bracket for mounting the sensor housing onto the support structure contribute to the difficulty of establishing the precise length of the air gap between the sensor and the target surface. In addition, the location of the sensor and target surface may be hidden and therefore it may be difficult, expensive, and impractical to precisely measure. Consequently, there is a need to minimize the stack-up of tolerances.
The invention provides a means to minimize the stack up of tolerances by incorporating the mounting bracket with the spool assembly of the sensor. The incorporation of the mounting bracket with the cap eliminates a step in the assembly of the sensor to the support structure. The design of the cap and mounting bracket assembly also reduces the height of the reference surface of the cap to the tip of the sensor. Therefore, the airgap is reduced and the overall cost of the internal components in the sensor is reduced.
The cap and spool assembly are modified to include elongate apertures and grooves respectively to receive portions of the mounting bracket. Tension means disposed between the cap and spool assembly maintain the portions of the mounting bracket within the elongate aperture and grooves. The cap further includes locking or snap fit features for securely attaching to hooked portions on the mounting bracket.
Other applications of the present invention will become apparent to those skilled in the art when the following description of the best mode contemplated for practicing the invention is read in conjunction with the accompanying drawings.